DE 41 02 529 A1 discloses a tool holder for rotating cutting tools, especially ones having a rod extending in the direction of the axis of rotation and introducible into a tool seat of a chuck, and having a cutting element mounted eccentrically on one end of the rod. The tool seat is eccentricity adjustable relative to the axis of rotation being mounted for adjustment of the operating radius of the cutting tool. For this purpose, there is mounted in an external bushing of the tool holder a circular opening eccentric from the axis of this bushing. In this opening, an interior bushing has an adjustable-rotation seat eccentric relative to the central axis of the opening for the cutting tool. The extent of the eccentricity between the seat for the cutting tool and the central axis of the opening in the exterior bushing in which the interior bushing is seated is more or less as great as the extent of the eccentricity between the central axis of the opening referred to and the exterior bushing. With the tool holder as disclosed, it is possible only to exchange a cutting element mounted on a rod for it by the holder in the form of a chuck, while the cutting element itself is mounted conventionally, eccentrically, on the free frontal surface of the rod which may be introduced into the chuck. Because of the large number of components, this tool holder as disclosed is complex in structure and accordingly expensive. Consequently, high-precision machining with that holder also is not possible.
Another tool is disclosed by DE 100 52 016 A1. The tool disclosed is used in particular for rotary milling and has as holder a shaft defining the axis of rotation. This holder may be coupled to a rotary drive, and has on its free end a headpiece to which a cutting element may be detachably connected in a mounting configuration in which the cutting edge of the cutting element is positioned at a radial distance from the axis of rotation corresponding to a desired cutting circle diameter. A supporting component on the headpiece performing the function of half-element of the cutting element is mounted so as to be rotatable around an adjustment axis which extends in parallel with the axis of rotation of the shaft and is offset eccentrically from this axis. It is possible to mount the cutting edge of the cutting element as a machining component offset a certain radial distance from the axis of adjustment. In addition, in the case of the solution disclosed, a stop mechanism is present by which the cutting element component may be locked with the headpiece in selected rotary positions which correspond to the diameter of the cutting circle diameter desired of the cutting edge of the cutting element.
In the case of the tool disclosed, the seat has convergent support surfaces of a support area which may be brought into contact with correspondingly convergent contact surfaces of the supporting component. A clamp connection is used to fasten the supporting component in the seat of the holder, there being provided as fastening component a hexagon socket screw which extends through the exterior circumferential wall of the seat in the holder. The machining component presses against the support surfaces of the support area of the seat. Although this configuration permits very good adjustment of the cutting component in the holder, it is desirable as a prerequisite for high-precision machining with the cutting element that the fastening be even further improved in order that high-precision machining may be achieved.
FR-A-1497 546 discloses a generic tool for machining by cutting having a holder with a fastening shank on one of its ends and on the other end a seat for a replaceable cutting element with a supporting component which is engaged at least partly in the seat when in the fastened state, and having a machining component. It is possible to fasten the supporting component in the seat by clamping by a fastening component. In the case of the disclosed solution, the shaft of the supporting component is cylindrical in configuration and may be fastened in a cylindrical seat by a fastening component which is integrated with the remainder of the seat by a slot guide and which may be tightened by a screw connection in the direction of the supporting component for the purpose of fastening the latter. As a result, there necessarily is a slight displacement of the axes of rotation of holder and supporting component which cannot be effectively offset in that there are inside the cylindrical seat three webs projecting into the seat space, the purpose of which is to permit center adjustment. High-precision machining with the tool is not possible. Comparable considerations also apply to the generic tool disclosed in GB 598 240 A.
U.S. Pat. No. 1,765,362 discloses clamping of the respective tools by a clamping or fastening sleeve in the case of a holder for drilling tools. The cylindrical seat has a plurality of slots in the direction of the fastening shank in diametrically opposite directions relative to the longitudinal axis. Thus, the tools may be clamped by screwing the fastening sleeve onto an external threading of the slotted fastening area of the drill on its shaft-like supporting component. The slotted guide necessitates fastening of the slotted fastening area of the cylindrical drill shaft by four elastic tongue areas in adjustment of the fastening sleeve. This in turn results in overevaluation of the fastening state for the supporting component and accordingly in displacement of the corresponding positions of the longitudinal axes of holder and drilling tools, something which in its turn results in machining inaccuracies.